• 정보통신설비학회논문지
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• 제10권4호
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• pp.121-127
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• 2011

Many peer-to-peer (p2p) systems have been studied in distributed, ubiquitous computing environments. Distributed hash table (DHT)-based p2p systems can improve load-balancing even though locality utilization and user mobility are not guaranteed. We propose a mobile locality-based hierarchical p2p overlay network (MLH-Net) to address locality problems without any other services. MLH-Net utilizes mobility features in a mobile environment. MLH-Net is constructed as two layers, an upper layer formed with super-nodes and a lower layer formed with normal-nodes. Because super-nodes can share advertisements, we can guarantee physical locality utilization between a requestor and a target during any discovery process. To overcome a node failure, we propose a simple recovery mechanism. The simulation results demonstrate that MLH-Net can decrease discovery routing hops by 15% compared with JXTA and 66% compared with Chord.

• 한국통신학회논문지
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• 제33권6A호
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• pp.666-675
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• 2008

현재 IEEE 802.22에서는 스펙트럼 사용 효율을 높이고 새로운 무선 통신 서비스 도입을 용이하게 하기 위한 연구가 활발히 진행되고 있다. 또한 TV 대역을 대상으로 주파수를 공유하고자 하는 Cognitive Radio를 적용한 WRAN 시스템에 대한 표준화가 진행되고 있다. 본 논문에서는 WRAN 시스템에서의 주파수 효율과 채널 용량을 극대화하구 인접 셀 간 간섭을 최소화할 수 있도록 하는 효율적인 주파수 할당 기법과 최적 전력 제어 기법인 PCPWF(Partial Constant Power Water Filling)을 제시하였다. 또한 제안된 동적 셀 설계(dynamic cell plan)를 통해 가용할 수 있는 채널을 효율적으로 할당하여 전체 시스템의 데이터 처리율(throughput)과 형평성을 극대화하였으며, 제안된 기법의 효용성을 검증하기 위해서 시뮬레이션 결과도 수록하였다.

• 한국지하수토양환경학회:학술대회논문집
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• 한국지하수토양환경학회 2000년도 추계학술대회
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• pp.171-176
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• 2000

Bioremediation of hazardous hydrophobic organic compounds, such as polycyclic aromatic hydrocarbons (PAHs), is a major environmental concern due to their toxic and carcinogenic properties. Due to their hydrophobicity, the hydrophobic organic compounds are mainly associated with the soil organic matter or nonaqueous-phase liquids. A major question concerns the relationships between biodegradation and sorption. This work develops and utilizes a non- steady state model for evaluating the interactions between sorption and biodegradation of phenanthrene, a 3-ring PAH compound, in soil-slurry systems. The model includes sorption/desorption of a target compound, its utilization by microorganisms as a primary substrate existing in the dissolved phase and/or the sorbed phase in biomass and soil, oxygen transfer, and oxygen utilization as an electron acceptor. Biodegradation tests with phenanthrene were conducted in liquid and soil-slurry systems. The soil-slurry tests were performed with very different mass transfer rate: fast mass transfer in a flask test at 150 rpm, and slow mass transfer in a roller-bottle test at 2 rpm. In the slurry tests, phenanthrene was degraded more rapidly than in liquid tests, but with a similar rate in both slurry systems. Modeling analyses with several hypotheses indicate that a model without biodegradation of compound sorbed to the soil was not able to account for the rapid degradation of phenanthrene, particularly in the roller bottle slurry test. Reduced mass-transfer resistance to bacteria attached to the soil is the most likely phenomenon accounting for rapid sorbed-phase biodegradation.

• KSII Transactions on Internet and Information Systems (TIIS)
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• 제14권7호
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• pp.2815-2839
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• 2020

In a cloud computing paradigm, allocation of various virtualized ICT resources is a complex problem due to the presence of heterogeneous application (MapReduce, content delivery and networks web applications) workloads having contentious allocation requirements in terms of ICT resource capacities (resource utilization, execution time, response time, etc.). This task of resource allocation becomes more challenging due to finite available resources and increasing consumer demands. Therefore, many unique models and techniques have been proposed to allocate resources efficiently. However, there is no published research available in this domain that clearly address this research problem and provides research taxonomy for classification of resource allocation techniques including strategic, target resources, optimization, scheduling and power. Hence, the main aim of this paper is to identify open challenges faced by the cloud service provider related to allocation of resource such as servers, storage and networks in cloud computing. More than 70 articles, between year 2007 and 2020, related to resource allocation in cloud computing have been shortlisted through a structured mechanism and are reviewed under clearly defined objectives. Lastly, the evolution of research in resource allocation techniques has also been discussed along with salient future directions in this area.

• 대한지역사회영양학회지
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• 제4권4호
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• pp.587-593
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• 1999

The purpose of this study were to : (a) analyzed price elasticity of university students in foodservice operations and (b)provide insight for price decision-making. Questionnaires were composed of price elasticity, the utilization and opinions of students on university foodservice operations, and demographic information regarding respondents. The questionnaires were distributed to 600 university students of 6 universities located in Seoul. Statistical data analysis was completed using the SAS package for descriptive analysis, t-test, ANOVA, and Pearson’s correlation. The results of this study can be summarized as follows: The average price for lunch was ￦1,663 for campus food, and ￦2,965 for off-campus restaurants. The frequency of utilizing the university cafeteria was fairly high. Students felt that the proper price for lunch was ￦1,446, presenting a lower price than the actual average price for lunch. The price elasticity was investigated in relation to the change in utilization rate when these was a price increase. The price elasticity was 2.03, with significant differences between sex, age, and major. The groups utilizing the university cafeteria frequently, taking longer time to go to off-campus or that were satisfied with the university cafeteria, had a lower price elasticity than those that did not. The results of this study suggest that predicting the price elasticity of the target market would assist the pricing policy, and the fact that the same students have different price elasticity by place and atmosphere can be used in marketing strategies.

• 반도체디스플레이기술학회지
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• 제7권1호
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• pp.29-34
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• 2008

In this paper, the DE(double erosion) cathode for the reactive magnetron sputtering system is developed for high deposition rate and high target utilization efficiency. The utilization efficiency of the developed DE cathode is 22% higher than that of normal SE(single erosion) cathode. Sputtering process for the nickel oxide thin films with the DE cathode is performed under the following conditions; power with $1kW{\sim}3kW$, pressure with 4mtorr and 8mtorr, oxygen flow ratio with $0%{\sim}80%$. As a result, the hysteresis phenomenon of discharge voltage in 4mtorr is lower than that in 8mtorr and the hysteresis phenomenon of discharge voltage is getting lower as the applied power is getting higher. The structure of cross section and surface roughness of the thin films are observed by FE-SEM and AFM. The structure of cross section of the thin films is columnar and the average surface roughness under oxygen flow ratio of 0%, 52.5% and 65.0% are $2.08{\AA}$, $2.20{\AA}$ and $0.854{\AA}$, respectively.

• 신재생에너지
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• 제19권1호
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• pp.41-52
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• 2023

Various carbon upcycling technologies have been proposed and are under development to achieve Korea's carbon neutrality target. Many chemical reactions are under development through various chemical reaction pathways, and different technological maturity levels are shown for each country and company. In this situation, it is essential to establish investment decisions such as research funds and human resources allocation through technological and economic analysis for close commercialization technologies and basic technologies with low technology readiness levels (TRL). Therefore, in this study, the technology development priority for developing carbon upcycling items was selected according to the domestic Carbon Capture & Utilization (CCU) technology roadmap using the stakeholder selection tool released by EU CarbonNext. As a result of the analysis, the TRL level of Korea's major carbon upcycling technologies was analyzed to be lower than that of other carbon resource technologies, and it was considered desirable to invest in mineral carbonization technologies among various candidate technologies.

• 정보관리연구
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• 제39권1호
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• pp.83-108
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• 2008

이 연구에서는 대학도서관의 장애학생 지원 실태를 조사하였다. 서울 경기 지역에 소재한 사립대학들 중에서 2008년도 특수교육대상자 특별전형을 시행한 30개 대학의 도서관을 대상으로, 그 대학의 장애학생들은 도서관을 어느 정도 이용하는지, 장애학생을 위한 시설 및 기자재, 자료, 그리고 전담 직원이 현재 적절하게 운영되고 있는지, 그리고 실제로 설치 유무를 조사하였다. 조사 결과, 대학도서관에 장애 학생을 위한 전반적인 운영 수준은 "보통" 이하(평균2.38)로 조사되었으며, 이용률은 "별로 이용하지 않는다"(60.0%)로 응답한 대학이 가장 많았다. 대학도서관의 시설 및 서비스 등의 응답률에서는 "매우 미흡"을 응답한 대학이 99건(32.27%)으로 가장 많았고, "매우 우수"를 응답한 대학이 28건(7.0%)으로 가장 적은 응답수를 나타냈다. 한편, 부문별로 분석했을 때, 건물의 시설은 모든 항목에서 "보통" 이상(평균3.26)의 수준을 갖추고 있으나, 자료구비수준(평균1.8점)과 장애 학생에 대한 원활한 지원을 위한 직원교육과 장애 학생들을 대상으로 한 도서관 이용교육(평균1.87)은 "미흡" 이하의 수준이었다. 특히, 서비스 부문은 "미흡"(평균2.48)의 수준으로, 표준편차는 1.4이상으로 인력배치와 자료배달 서비스는 대학 간의 편차가 가장 큰 부문이었다. 따라서, 대학도서관은 시설 등의 접근성은 상당 수준 개선되었으나, 자료, 인력 및 이용교육과 같은 도서관 고유의 정책은 일반적으로 미흡한 수준에 있다고 조사되었다.

• 대한안전경영과학회지
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• 제15권4호
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• pp.245-251
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• 2013

In this paper, the expert system to reduce the amount of food waste is proposed. The method of material flow analysis (MFA) is applied. Proper handling of waste beyond the terms of the need for proactive research been mentioned before, but actually cause the waste generator research focuses on consumer behavior and the business community to analyze the flow of materials within the study are insufficient. In this paper, the type of food consumption and food waste, look at the relationship between the occurrence of secondary schools in the diet is provided for students to examine the preferences of the target model diet expert system was reconfigured. Preference for leaving the food in the diet leads to the important information that is Each diet recipes that make up the target material flow analysis (MFA) was constructed to perform all the database. This database is currently being generated from the rain while cooking diet edible plants and materials to reflect the self-esteem following the recommended diet is used to create. Reducing food waste is actually being used currently in research knowledge to the knowledge base was constructed. Future Home Smart System was developed in conjunction with the system to the user, by providing guidelines for the utilization can be expected.

• 대한간호학회지
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• 제30권4호
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• pp.932-947
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• 2000

The purpose of this study was to suggest directions for developing a Health Promotion Program for the elderly in Korea for the future. For this, twenty previously developed & implemented health promotion programs were reviewed and analyzed in terms of target population of the program, components of the program, measurement variables for effects of program, the effects of the program. The results were as follows. 1. Most of the target populations were older adults living independently in the community. 2. Components of the program were health education, health assessment and counseling and exercise program. - Health education was done in most of programs. The topics of health education that were often included in the programs were life style changes, medical knowledge, independent living, the concept of health promotion and changes related to aging. - In health assessment and counseling, health professionals discovered their health problems through health assessment or health risk appraisal. Then they developed health recommendations on each health problem and encouraged the elderly to implement the recommendations. 3. Variables measuring the direct effects of the program were health behavior, knowledge, attitude, skill, use of medical/health reference book. Variables measuring the indirect effects, biometric outcome, health status, functional status, medical service utilization, medical cost and wellbeing. 4. The analysis showed that health education was effective for changing health behaviors, improving knowledge, skill and attitude in the elderly. Those results were suggested to be used as guidelines for developing a health promotion program for the elderly in Korea for the future.